This invention relates to an image forming apparatus and method for forming a monochromatic or color image a recording medium.
In an image forming method according to the prior art, a technique is known in which the stability of image quality is improved by forming one specific pattern on a recording medium, reading the intensity of the pattern of the recorded image and feeding the read intensity back to control image forming conditions such a xcex3 correction. This technique makes it possible to stabilize image quality in conformity with an amount of fluctuation in characteristics due to long use and an amount of fluctuation in environmental conditions.
With the example of the prior art described above, however, any skewing or deviating of the recording medium when the recording medium having a gray-scale pattern (intensity data) is placed upon a platen and read can result in the wrong data being read in. When feedback to the image forming conditions is performed using this data, an optimum image cannot be obtained.
Furthermore, in the above-described example of the prior art, there are instances in which an abnormally sudden fluctuation in intensity occurs owing to an abnormality in the image forming apparatus despite the fact that a uniform intensity is outputted over the full surface of the recording medium in the image forming apparatus. When feedback to the image forming conditions is performed using this data, the optimum image cannot be obtained.
An object of the present invention is to provide an image forming apparatus and method in which an image forming condition is properly controlled. For example, an object of the present invention is to provide an image forming apparatus and method in which, when a recording medium on which a gray-scale pattern has been formed is placed upon a platen in a skewed attitude, the offset is corrected and the image forming conditions are adjusted, whereby an ideal image is obtained.
Another object of the present invention is to provide an image forming apparatus and method in which, if an abnormal portion is found in an intensity value of a gray-scale test pattern when the pattern is read in, notification is given of the fact that some abnormality has developed, thereby making it possible to prevent an erroneous operation, and in which maintenance is facilitated by estimating the location at which an abnormality has occurred.
According to the present invention, the foregoing objects are attained by providing an image forming apparatus for forming an image on a recording medium, comprising pattern forming means for forming at least one-gray-scale pattern on a recording medium, correcting means for correcting positional deviation of the gray-scale pattern, which is formed by the pattern forming means and controlling means for controlling an image forming condition on the basis of the gray-scale pattern whose position has been corrected by the correcting means.
Further, the foregoing objects are attained by providing an image forming method for forming an image on a recording medium, comprising the steps of forming at least one gray-scale pattern on a recording medium, correcting positional deviation of the gray-scale pattern, which is formed at the forming step and controlling an image forming condition on the basis of the gray-scale pattern whose position has been corrected at the correcting step.
In another aspect of the invention, the foregoing objects are attained by providing an image forming apparatus comprising image forming means for forming an image, pattern forming means for forming a specific gray-scale pattern, reading means for reading the gray-scale pattern formed by the pattern forming means and generating image data, controlling means for controlling an image forming condition on the basis of the image data, and discriminating means for discriminating whether the image data generated by the reading means is suitable for being used by the controlling means.
Further, the foregoing objects are attained by providing an image forming apparatus comprising reading means for reading an image formed on a medium and generating image data, pattern generating means for generating pattern data representing a gray-scale pattern and a standard point, image forming means for forming an image on a medium in accordance with the image data or the pattern data, and controlling means for controlling an image forming condition of the image forming means based on a gray-scale pattern formed on a medium and read by the reading means, wherein the controlling means includes discriminating means for discriminating a standard point formed on the medium and read by the reading means.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts in the figures thereof.